English Medium कक्षा १० - CBSE Question Bank Solutions for Science

How do you think the brightness of two lamps arranged in parallel compares with the brightness of two lamps arranged in series (both arrangements having one cell)?

In which of the following cases more electrical energy is consumed per hour?

(i) A current of 1 ampere passed through a resistance of 300 ohms.
(ii) A current of 2 amperes passed through a resistance of 100 ohms. 

For a heater rated at 4 kW and 220 V, calculate:

(a) the current,
(b) the resistance of the heater,
(c) the energy consumed in 2 hours, and
(d) the cost if 1 kWh is priced at Rs 4.60.

Two lamps, one rated 40 W at 220 V and the other 60 W at 220 V, are connected in parallel to the electric supply at 220 V.  

(a) Draw a circuit diagram to show the connections.
(b) Calculate the current drawn from the electric supply.
(c) Calculate the total energy consumed by the two lamps together when they operate for one hour.

An electric bulb is rated as 10 W, 220 V. How many of these bulbs can be connected in parallel across the two wires of 220 V supply line if the maximum current which can be drawn is 5 A? 

How does the heat H produced by a current passing through a fixed resistance wire depend on magnitude of current I?

If the current passing through a conductor is doubled, what will be the change in heat produced

Which effect of current is utilised in an electric light bulb?

Which effect of current is utilised in the working of an electric fuse?

Name two devices which work on the heating effect of electric current.

State three factors on which the heat produced by an electric current depends. How does it depend on these factors? 

State the two laws of reflection of light.

Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.

Distinguish between an open and a closed circuit.

State the relation between work, charge and potential difference for an electric circuit.

Answer the following question.
An electric lamp of resistance 20 Ω and a conductor of resistance 4 0 are connected to a 6 V battery as shown in the circuit. Calculate: 

(a) the total resistance of the circuit,  

(b) the current through the circuit, 

(c) the potential difference across the  (i) electric lamp and (ii) conductor, and

(d) power of the lamp.

At the time of short circuit, the electric current in the circuit ______.

Answer the following question.
What is the function of a galvanometer in a circuit?

Two electric bulbs rated 100 W; 220 V and 60 W; 220 V are connected in parallel to electric mains of 220 V. Find the current drawn by the bulbs from the mains.